Along with the advancement and popularization of information technology, storage apparatuses capable of reading and writing data with respect to storage media, such as magnetic disks, optical disks, and semiconductor memories are in wide use in recent years. The use of such a storage apparatus facilitates large amounts of data to be stored in storage media. Some storage apparatuses use a part of storage media as a backup area in which a copy of original data is stored as backup data in order to prevent destruction of the original data. The following technologies are known in regard to free space management of storage media.
Japanese Laid-open Patent Publication No. 2004-280333
Japanese Laid-open Patent Publication No. 2010-86393
When writing and deletion of backup data are repeated in a storage apparatus, it is sometimes the case that an area for storing backup data becomes discontinuous. In the case where a backup area used to store backup data is discontinuous, the load on the storage system, such as processing load associated with reading and writing of the backup data and management, may increase.